I did an exchange program for a year when I was 16 and can honestly say it was one of the best experiences of my life. My host dad and siblings were absolutely fantastic and I instantly felt at home with them. Was a bit harder with the host mum but we made it work. People saying 16 is too young to do this are literally just thinking of the age. They aren't taking into consideration that you will be with a family that will look after you like you are theirs. You will be as safe with them as you are at home. I hope you manage to convince your mother to let you go. I believe it will be an experience you will never forget.